Just finished watching the anime http://lagooncompany.wikia.com/wiki/Black_Lagoon_Wiki (again). In This anime, the Black Lagoon shipping company is based out of a fictional town called Roanipur. It is near the China Sea in the South Pacific. It is a beautiful setting in itself.
http://lagooncompany.wikia.com/wiki/Roanapur though, is the hub of criminal activity. It is peopled by thugs, women of the night, and differing mafia galore. Every time I watch this anime, I think what a great video game setting this could be. Guns rule the city. One of the local hangouts, The Yellow Flower gets blown sky high nearly every time the Black Lagoon company spends any downtime there
This game could have a Grand Theft Auto feel to it, but almost every action sends in motion reactions to any event. Retaliations, schemes, schemes within schemes could be so possible. Factions would be a huge part of the game. Bribing the local police would be important. Skill sets and combat animations would need to be over the top.
I am not usually a player who enjoys playing evil, or lower morality type characters, but imagining this game has me wanting to play something like it. I guess being evil in a cesspool of evil is not so bad
Here is a YouTube fan video of the series that captures the feel of it fairly well
https://www.youtube.com/watch?v=pFN0qeN6Sdg